I think the only pubs are in Bala itself.
It's a good few miles down the lakeside to the campsite that we use but it does allow fires on the shore, so you can substitute with tinnies around the campfire. (The pubs in Bala ain't so special imho)

Rode from Chester to here the other weekend, camped and back. (no idea how to do links...)

tyisafbala.co.uk/

Very nice, quiet and friendly, and only a fiver!
Basic and I'd recommend the field at the farm rather than the river frontage field, walked down there but loos are enough to put you off...
Farm field was ace though. Mile and a bit to the pubs but all the sites in Bala are the same.

Commander, that one near Bala looks nice, I hadn't realised they split the camping from the caravanning. It can be difficult to find good campsites near pubs in Wales, the nicer, quiter sites tend to be in farmer's fields in the middle of nowehere, like Cae Du that always get recommendations here (3 miles from Tywyn but fantastic views). You could also try Cae Adda in Trawsfynydd (has a pub in village). But if you are looking to book for this weekend, you might struggle with those. If so, try searching ukcampsite.

EDIT: And if you want quiet, and you are looking for this weekend or any time in the summer holidays, avoid Snowdonia and Bala! Around Llyn Vyrynwy or Clywedog or the Elan valley is just a beautiful.

Just got back from a weekend of adventure racing in the area - we were staying at Cae Adda. Lovely site, nice owners, good facilities, and right on the shore of the lake - great for swimming and kayaking.

Always use Ty Isaf now, I've stayed in all of them and its the best if you just want to pitch up and camp. Basic but good, cheap and always a space even on summer bank holiday. The owners of the rest all seem to be a bit mardy, especially if you have a group. It's normally fairly quiet, no noise late at night. If there's a few of you, just drive into town and get a cab back (I've walked it a few times, not too bad a walk if you have a tinny or too.) Or beers and a fire at the campsite.